The advantage of RFID transponders compared to the barcodes predominantly used in particular in the goods marking sector is that they permit a direct exchange of information, meaning that no visual contact is needed between the interrogating device and the transponder for the information transfer. Unlike barcodes, furthermore, it is an easy matter with RFID transponders to change their information content directly as and when required.
RFID transponders are constructed as either passive or active elements. If the RFID transponder is used as an active element, the housing enclosing the integrated circuit contains an additional energy source usually in the form of a battery. RFID transponders are able to operate in the most diverse frequency ranges, for example, in the low frequency range at 125 kHz, in the medium frequency range at 13.56 MHz or in the microwave range at typically 2.45 GHz. The present invention relates preferably--but by no means exclusively--to passive transponders operating in the medium frequency range.
A data carrier with an integrated circuit is known in the art from European Patent EP 0 682 321 A2. This data carrier is comprised of a card body and an integrated circuit connected electrically via contact elements to at least one oil composed of one or several layers. The two elements combine to form a resonant circuit which operates at a predetermined resonant frequency. The purpose of the coil is to supply energy and/or to exchange the data of the integrated circuit with external devices. Circuit and contact elements are constructed as a separate module.
The disadvantage of the known RFID transponders compared to barcodes is the immense difference in price between the two elements. This is also the reason why the use of RFID transponders in the sales sector has been restricted so far to fringe areas. In particular there has been no interest to date in using RFID transponders to present price information or other data when selling mass products in department stores and warehouses. Up to now an RFID transponder has cost in the region of about 16, which naturally makes their use as disposable identification markers completely out of the question.
It will be understood, of course, that RFID transponders find application in the most diverse areas, particularly in the fields of production, further processing and transportation of goods as well as in security applications. Examples include the identification marking of people and animals, the identification marking of baggage and packages, particularly at airports and post offices, and the identification marking of vehicles during their production or in multistory car parks.